Advantech Motherboard DAC-BC05 - Power but doesn't start

[samstown]

Hello,

This is my first post. Long story short... This motherboard run the Touch cash register at my friends restaurant. He paid that Touch Cash register a heavy price three years ago.. and that device doesn't start anymore. Of course the reseller said it's out of warranty and offer to replace the device for 2000 USD !

My friend was really unhappy has he had to close for long period due to covid and now that device fail and he doesn't have money to replace it. The device was working... and the next day, no way to boot it, black screen...

So I took a look, it doesn't really looks bad... but I can't fix it by myself. The device is powered by an external power supply. When plugged, I can see 5VSB LED on. When press power button the other led 5V also turn's on and I can hear the HDD starts to spin.. but no image.

Worst case scenario, it could be graphic chip failure ?... I hope it's not. I've disconnected the Touch screen and I've connected VGA monitor but still, nothing. I've removed RAM, CMOS battery, I did the CMOS reset with the jumper, doesn't help. I don't head any "bip" when I power it.

I don't see anything wrong on PCB, no short, no bad smell... I've google it, couldn't find a lot of information on that motherboard. I've search on this forum as well then I decided to post.

If you guys have an idea, I'll be happy to try everything..

Thank you
Sam

[mon2]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

Hi. This is an industrial style motherboard. You may be able to locate the same board, used on ebay at fair costs. Advantech is a large and active company. We supply them in Asia for some of our mutual accounts.

Varying with your interconnected parts, a standard pc could also work here.

First, touch any metal frame that is grounded to discharge your body to not zap these logic boards.

Can you test another monitor? Could the issue be the external monitor?

In the meantime, power down, remove the memory stick, remove the sata red cable. Power up.

Do you hear any power up beep pattern to inform you that the ram is missing?

Do you have access to a multimeter?

If yes, use voltage mode setting and carefully check the voltage on the board at the dc input. Black probe on ground. Red probe on the +5volt input to the logic board. Turn on the logic board, does the input rail remain at +5v0 ?

Often power supplies or power rails fail over time.

Assuming above is ok, power down and unplug the power source from your AC wall socket. Then turn on again to discharge any energy in the external power adapter.

Next use your meter in resistance mode with black probe on ground, red on the small black parts marked 220 and have a "+" on them. Apply red probe on the "+" side. What is the resistance?

Over time, these tantalum caps can internally short and this will cause the power regulator to shutdown to prevent damage due to excessive current being drawn.

Do this check on each capacitor on the board. What are the values in ohms?

If the value is very low, then one of the caps is shorted.

Plan B is to search for a replacement mother board for a quick swap out. They are not $2000 boards. Will check around once fully awake here..

[mon2]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

https://www.ebay.com/itm/273572783161

[samstown]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

Hello Mon2, can you so much for your quick reply. I have a multimeter, I'll do the test and get back to you shortly.

[samstown]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

Ok, so i've tested monitor on VGA source with two working PC, monitor is ok.

The power supply give 12 V.

I've remove RAM, SATA connector, doesn't help.

When I plug the power supply I can hear the little bip from the speaker, it's not bip as PC starting, it's really the bip when you plug power.

I have current on HDD, on little speaker, on the 5 V Led... Caps looks ok as far as I can tell, I've printed what I measure on the pics below.

[mon2]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

The cap resistance look ok.

Remove the CR2032 battery from its socket and leave it out. With this battery removed, the BIOS chip should load up fail-safe default values to power up.

With your meter in voltage mode, power on with black probe on ground and red probe on each inductor which will be the grey looking squares on the logic board. They will have a "Lx" marking on the white silk screened text.

These inductors are linked to a local power supply rail. Each inductor should offer some voltage to run the respective power rail.

Suspecting that some power rail after you receive the main external adapter source has failed. If and when this is located, the respective surface mount component(s) must be replaced.

Please proceed to confirm the rails for the inductors (see 2R2 = 2.2 uH; and see 1R0 = 1.0 uH) on your shared pix.


May be a good idea for the shortest downtime to source a replacement logic board to be operational asap. The link that was shared appears to be from a vendor in China. Advantech is a large company and have met them in Taiwan over the years, you most likely have a local European branch of their firm. First contact should be with Advantech Europe to ask for advice and this same logic board. If you hear the "no longer available" then consider the alternate sources. There are numerous ebay listings for this logic board.

You can validate the hard drive with another PC as a SLAVE drive. Then confirm that the contents look to be ok. As noted, this appears to be a condensed motherboard with perhaps some POS interconnects for cash drawers, etc. I know that we were asked by HP to design such models but it is a very competitive and saturated market. Most likely the POS s/w is on the hard drive. As a general rule, suggest to source a SSD and make a bit copy clone for safe keeping. Just be very gentle with any mechanical drives as they do fail. SSD drives are quite cheap these days. Suggest the SAMSUNG EVO series. I believe they are up to EVO 870 series as of last week.

[samstown]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

Thank you for your help.

I've remove battery, doesn't help.

L5 ( R47) only has 0.06 V ? Maybe we are on something ?

For my curiosity, what are the bucket I've circle in blue, caps as well ?

[mon2]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

Hi.

1) The circled parts are also capacitors but electrolytic polymer kind. The few in the pic appear to be 270 uF @ 16Volts rating. Not sure of their current rating at this time.

2) Yes the voltage read on L5 appears too low to be practical. Most likely it is linked to the component to the left side = Q5.

Can you share the full markings on Q5? Even better if you can take a quality close up picture of Q5.

3) Next, with the POWER OFF, measure the resistance to ground on L5 so we can check if the resistance is ok on that voltage rail.

[samstown]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

thank you.

1. thanks
2. I've attached a pics of Q5. IORP241H
3.L5 = 80 Ohms

[mon2]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

The resistance looks ok if this is indeed a low voltage power rail which suspecting it to be. From the reading, this rail does not appear to be operational.

Q5 is from International Rectifier.

However, unable to locate a datasheet for this device. The package is a SOIC8. Perhaps someone else in the forum will recognize this component.

[samstown]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

Thank you so much mon2 !! One big step... I took heat gun and put 10 seconds heat on that area where Q5 is... and PC now boot. after few 3-4 minutes, PC die but I can reproduce it... apply heat, boot.. then die.

could be Q5 ? Transistor like heat.. to open gate ?

[mon2]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

OMG!! That is such good news. I think you are truly onto the root issue. The component should be replaced but unable to locate it as of this writing. Perhaps some other nearby component is impacting this operation but still believe this is a defective part.

For clarity, once it is working, please measure the voltage on the coil.

Someone with more experience with International Rectifier parts may be able to recognize the proper markings on this component.

Update:

After the unit fails, do you find that this Q5 is hot or very warm to the touch? Carefully monitor this.

Do you have alcohol (electronic kind is best for its purity) in your setup? You can try to place some alcohol on the component when it dies to see if the alcohol evaporates quickly or not. Just an idea.

Another thought...perhaps the use of ROHS solder paste / soldering is taking a toll on this motherboard. They say that over time, solder whisker growth can creep in and cause havoc. Also a possibility of a solder joint that is breaking the circuit. Assuming this as a fault, you could apply your heat gun with low air pressure so that the parts do not go flying over the region. This should allow for the solder joints to melt and make a fresh connection again. If you have some solder flux, you could apply onto Q5 for starters when performing this reflowing of the solder connections. Please proceed carefully so that no parts are disturbed off the motherboard.

[SMDFlea]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

The part number is F79O4 https://cdn.badcaps-static.com/pdfs/...d708e81ff8.pdf

The solder on one side of L5 looks cracked.

[mon2]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

@SMDFlea - brilliant stuff. Learning something new every day

Thanks!

So a current replacement for Q5 is:

IRF7904TRPBF

and available from Mouser and most likely others:

https://www.mouser.ca/ProductDetail/...6P4tUsyg%3D%3D

Datasheet is attached.

[samstown]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

Hello mon2 , SMDFlea,

I am very happy I found this forum and this great community of expert !

Thank you so much for your help. This morning, I've remove and solder mosfet, system is working properly, it was only a bad contact/cold solder

My friend is super happy !! If you visit Switzerland one day, let me know, I/He owe you a meal

This case can be marked as closed.

Quick note : VGA port doesn't work on those board. When PC boot I get "not supported", so it's at least better than the "no signal" I was getting before fixing MosFet but if somone need to troubleshoot this motherboard, better to know VGA won't give anything that "not supported" on the screen.

Thanks
Sam

[Per Hansson]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start

Quick note : VGA port doesn't work on those board. When PC boot I get "not supported", so it's at least better than the "no signal" I was getting before fixing MosFet but if somone need to troubleshoot this motherboard, better to know VGA won't give anything that "not supported" on the screen.

Thanks
Sam

Nice team work!
Just a side note: it can also be that the monitor does not support the frequency or resolution being output on the VGA port.

[koiso32]

Re: Advantech Motherboard DAC-BC05 - Power but doesn't start


Can someone help me with those caps i can t find a replacement ,i tried searching online the code on them but with no luck!

https://ibb.co/GFw63qB